The present invention relates to automatic fare collection systems and relates particularly to read/write head assembly.
Automatic fare collection systems typically utilize high-speed transport units for accepting a magnetic ticket or card and transporting the ticket or card rapidly in one or both directions past a magnetic read/write head. In order to insure accuracy of the reading and writing on the ticket or fare card, it is essential that the card or ticket be positioned in a uniform position with uniform pressure against the read/write head. The principal biasing means for tickets in the past have been rollers positioned opposite the magnetic head for biasing the ticket into engagement with the head. Rollers, however, require very accurate and minute adjustments to maintain necessary pressure and clearance of the card against the magnetic read/write head.
Another way of applying pressure to the fare card which has been utilized by the assignee hereof in the past is to use a set of angularly inclined bristles made of a material such as nylon angled in the direction of movement of the card for biasing the card against the magnetic head. Such brush assemblies have been inclined only slightly from the path of the moving ticket or fare card and point in the direction of movement of the card. Such brush systems work very well where the card travels only in a single direction with the brush bristles pointing in that direction. However, recent systems utilize a reversing transport which reverses and transports the card back across the read head in the opposite direction. The typical brush pressure unit as used in the past will tend to buckle, and cause sudden changes in the speed of the fare card which can result in errors in reading or writing data. In addition, where unidirectional bristles are used, if the direction of the fare card is reversed, the proper amount of pressure of the fare card against the magnetic head may not be achieved.
It is therefore desirable that an improved pressure unit be available for magnetic read/write heads.